Question

What is a condition-controlled loop?

Short answer

Answer: A condition-controlled loop is a programming construct that repeatedly executes a block of code as long as a specified condition remains true. Once the condition becomes false, the program exits the loop and continues execution after the loop. This is different from count-controlled loops, which execute a predetermined number of times. Examples of condition-controlled loops include 'while' loops and 'do-while' loops in various programming languages, whereas count-controlled loops include 'for' loops.

Step-by-step solution

Introduction to Condition-Controlled Loops

A condition-controlled loop is a looping construct in programming, which repeatedly executes a block of code as long as a specified condition remains true. Once the condition becomes false, the program exits the loop and continues execution after the loop. Condition-controlled loops are commonly used for tasks that require repetition until a certain condition is met or is no longer true. Examples of condition-controlled loops include 'while' loops and 'do-while' loops in various programming languages.

While Loops

A 'while' loop is a type of condition-controlled loop that checks the specified condition before executing the code block inside the loop. If the condition is initially false, the code block will not be executed at all. This is an example of a 'while' loop in Python: ``` count = 0 while count < 5: print("Hello, World!") count += 1 ``` In this example, the loop will execute as long as the variable 'count' is less than 5. Each time the loop iterates, the value of 'count' is incremented by 1, eventually causing the condition to become false and the loop to stop executing.

Do-While Loops

A 'do-while' loop is another type of condition-controlled loop that first executes the code block and then checks the specified condition. If the condition is true, the loop will continue executing. If the condition is false, the loop will exit. This guarantees that the code block inside the loop will always execute at least once. While Python does not have a built-in 'do-while' loop, you can achieve similar functionality with the following code: ``` count = 0 while True: print("Hello, World!") count += 1 if count >= 5: break ``` In this example, the loop will execute the code block and then check if the 'count' variable is greater than or equal to 5. If it is, the loop will exit by using the 'break' statement. This ensures that the code block is executed at least once before checking the condition.

Comparison with other loop types

In contrast to condition-controlled loops, there are also count-controlled loops such as the 'for' loop. Count-controlled loops are designed to execute a predetermined number of times. For example, a 'for' loop in Python would look like this: ``` for i in range(5): print("Hello, World!") ``` In this case, the loop executes exactly five times, as determined by the range() function. In conclusion, condition-controlled loops, such as 'while' and 'do-while' loops, are used when the number of times a loop should execute depends on a specified condition. This is different from count-controlled loops, which execute a predetermined number of times. Understanding when to use condition-controlled loops is essential for efficient and effective programming.